Developing device and image forming apparatus

Abstract

The invention discloses a developing device and an image forming apparatus. The developing device includes: an image holder unit having an image holder; a developer unit having a developer holding body that supplies a developer to the image holding body on which the electrostatic latent image is formed; a support portion that supports the developer unit so as to be capable of advancing and retreating with respect to the image holding body unit; a first positioning portion that is provided at an end portion of the support portion on the image holding body unit side and positions the developer unit; and a second positioning portion that positions the developer unit while maintaining a predetermined gap between the developer holding body and the image holding body in a state where the developer unit is positioned by the first positioning portion and is tilted toward the image holding body unit side.

Description

Technical Field

[0001] The present invention relates to a developing device and an image forming device. Background Art

[0002] In an image forming apparatus based on an electrophotographic method, in order to accurately ensure the interval (hereinafter, "gap") between an image holding body and a developer holding body, an image holding body unit including an image holding body and a developer unit including a developer holding body are brought into contact with each other, so that the developer unit is positioned and fixed. In addition, in order to prevent the gap from changing due to a reaction force when the developer is driven or an external force from other parts of the image forming apparatus, a conventional technique is configured to push the developer unit onto the image holding body unit using the load of the developer unit itself.

[0003] In the gazette of Japanese Patent No. 4655569, there is disclosed an image forming device, which is composed of: a developer supporting member whose movement in the up-and-down direction is restricted and which can move in the left-and-right direction; a pushing force generating member for pressing the developer toward the photosensitive drum; and a tracking mechanism for maintaining the distance between the photosensitive drum (image retaining member) and the developing roller (developer retaining member) at a specified value in a state where a pushing force is applied by the pushing force generating member, wherein a photosensitive body side tracking member and a developing roller side tracking member in the tracking mechanism are in contact with each other, a height of a center position of the photosensitive body unit is arranged below a height of the developing roller, and the developing roller side tracking member presses the photosensitive body side tracking member from above. Summary of the invention

[0004] In a large-scale image forming apparatus, the developer is also large, so the reaction force during driving is also large. Therefore, the mechanism for pressing the developer toward the photosensitive drum against the reaction force during driving becomes complicated.

[0005] An object of the present invention is to generate a pressing force to press a developer against a photosensitive drum using a simple structure, compared with a structure using a member that generates a pressing force to press a developer against a photosensitive drum.

[0006] According to a first aspect of the present invention, a developing device is provided, which comprises: an image retaining body unit, the image retaining body unit having an image retaining body; a developer unit, the developer unit having a developer retaining body for supplying developer to the image retaining body on which an electrostatic latent image is formed; a supporting portion, the supporting portion supporting the developer unit so as to be able to advance and retreat relative to the image retaining body unit; a first positioning portion, the first positioning portion being provided at an end portion of the supporting portion on the image retaining body unit side to position the developer unit; and a second positioning portion, the second positioning portion maintaining a predetermined gap between the developer retaining body and the image retaining body to position the developer unit when the developer unit is positioned by the first positioning portion and tilted toward the image retaining body unit side.

[0007] According to a second aspect of the present invention, in the developing device of the first aspect, the supporting portion has a guide path for guiding the developer unit, the first positioning portion is configured to tilt the end of the guide path in such a manner that the image retaining body unit side is lowered, and has a supporting portion for the developer unit to abut at the inclined position of the guide path.

[0008] According to a third aspect of the present invention, in the developing device of the first or second aspect, the first positioning portion further includes a pressing member that restricts movement of the developing unit in a state in which the developing unit abuts against the abutting portion.

[0009] According to the fourth aspect of the present invention, in the developing device of the second or third aspect, the guide path of the supporting portion has two rails arranged in parallel along the direction of advance and retreat of the developing unit, and the first positioning portion is configured to tilt the ends of each of the two rails, and the end of one of the two rails has the abutment portion.

[0010] According to a fifth aspect of the present invention, in the developing device of the fourth aspect, the developing unit is not fixed to a rail of the two rails of the first positioning portion that does not have the abutment portion.

[0011] According to the sixth aspect of the present invention, in the developing device of any one of the first to fifth aspects, the supporting portion comprises: a lower guide path, which supports and guides the lower portion of the developer unit and has the first positioning portion; and an upper guide path, which supports and guides the upper portion of the developer unit, and when the developer unit is positioned by the first positioning portion of the lower guide path, the developer unit separates from the upper guide path and tilts toward the image retaining body unit side.

[0012] According to the seventh aspect of the present invention, in the developing device of the sixth aspect, when at least the developer unit is in a state where the developer unit is positioned by the first positioning portion of the lower guide path, the upper guide path of the support portion is capable of switching between a contact state of supporting the developer unit and a retreat state of separation from the developer unit.

[0013] According to the eighth aspect of the present invention, in the developing device described in the seventh aspect, the upper guide path of the supporting portion has two rails arranged in parallel along the direction of advance and retreat of the developer unit, one of the two rails in the upper guide path is capable of switching between the contact state and the retreat state, and the other of the two rails in the upper guide path is shorter than the moving distance of the developer unit and does not contact the developer unit when the developer unit is in a position positioned by the first positioning portion of the lower guide path.

[0014] According to the ninth aspect of the present invention, in the developing device of any one of the first to eighth aspects, there is also a driving mechanism, which rotates the driving shaft of the developer unit and transmits driving force to the developer unit, and the driving mechanism is capable of changing the position of the axis center of the joint part connected to the driving shaft and causing the driving shaft to rotate.

[0015] According to a tenth aspect of the present invention, there is provided an image forming apparatus including the developing device according to any one of the first to ninth aspects.

[0016] (Effect)

[0017] According to the first aspect, the developer can be pressed toward the photosensitive drum by a simple structure utilizing the load of the developer unit, compared with a structure using a member that generates a pressing force for pressing the developer toward the photosensitive drum.

[0018] According to the second aspect, compared with a structure in which a mechanism for fixing the developing unit is provided, the developing unit is positioned by its own weight, so that a simple structure can be adopted.

[0019] According to the third aspect, compared with a structure in which the movement of the developer unit is restricted only by the inclination of the guide path and the abutment portion, restriction of the movement of the developer unit can be suppressed more reliably.

[0020] According to the fourth aspect, a simpler structure can be achieved compared to a structure in which each rail has a contact portion.

[0021] According to the fifth aspect, compared with a structure in which the developing unit is fixed to each rail, the developing unit can be easily positioned and the load on the developing unit and the first positioning portion can be reduced.

[0022] According to the sixth aspect, compared with a structure in which a mechanism for fixing the developing unit is provided, the developing unit is positioned by its own weight, so that a simple structure can be adopted.

[0023] According to the seventh aspect, compared with a structure in which the upper guide path does not support the developer unit on the first positioning portion, the falling action of the developer unit can be suppressed.

[0024] According to the eighth aspect, a simpler structure can be achieved compared to a structure capable of switching between the contact state and the retracted state on each track.

[0025] According to the ninth aspect, compared with a structure in which the axial center position of the driving mechanism is fixed, it is possible to cope with the deviation of the axial center due to individual differences or changes over time in the developing device units.

[0026] According to the tenth aspect, compared with a configuration in which a member generating a pressing force for pressing the developer toward the photosensitive drum is used in the developing device, the developer can be pressed toward the photosensitive drum with a simple configuration utilizing the load of the developer unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A diagram for explaining an image forming apparatus to which this embodiment is applied;

[0028] Figure 2 is a diagram showing the internal structure of a developer;

[0029] Figure 3 is a diagram showing a structural example of an image forming unit;

[0030] Figure 4 is a diagram showing the overall structure of a developer;

[0031] Figure 5 is a diagram schematically showing a supporting structure of a developer, Figure 5 (A) is a diagram showing the support structure of the front side of the lower support roller, Figure 5 (B) is a diagram showing the support structure on the back side of the lower support roller. Figure 5 (C) is a diagram showing the support structure of the front side of the upper support roller, Figure 5 (D) is a diagram showing the support structure on the back side of the upper support roller;

[0032] Figure 6 2 is a diagram showing a state where the developer is in retreat. Figure 6 (A) is a diagram showing the state of the front side, Figure 6 (B) is a diagram showing the state of the back side;

[0033] Figure 72 is a diagram showing a state where the developer moves from the retreat position to the set position. Figure 7 (A) is a diagram showing the state of the front side, Figure 7 (B) is a diagram showing the state of the back side;

[0034] Figure 8 2 is a diagram showing a state where the developer has completed moving to the setting position. Figure 8 (A) is a diagram showing the state of the front side, Figure 8 (B) is a diagram showing the state of the back side;

[0035] Fig. 9 is a diagram showing a state where a developer is set. Fig. 9 (A) is a diagram showing the state of the front side, Fig. 9 (B) is a diagram showing the state of the back side;

[0036] Fig.10 is a diagram showing a driving mechanism of a developer;

[0037] Fig.11 1 is a diagram showing the adjustment sequence of the axis in the driving mechanism of the developer. Fig.11 (A) is a diagram showing the first state, Fig.11 (B) is a diagram showing the second state;

[0038] Fig.12 1 is a diagram showing the adjustment sequence of the axis in the driving mechanism of the developer. Fig.12 (A) is a diagram showing the third state, Fig.12 (B) is a diagram showing the fourth state;

[0039] Fig.13 1 is a diagram showing the adjustment sequence of the axis in the driving mechanism of the developer. Fig.13 (A) is a diagram showing the fifth state, Fig.13 (B) is a diagram showing the sixth state;

[0040] Fig.14 1 is a diagram showing the adjustment sequence of the axis in the driving mechanism of the developer. Fig.14 (A) is a diagram showing the seventh state, Fig.14 (B) is a diagram showing the eighth state. DETAILED DESCRIPTION

[0041] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0042] <Structure of image forming apparatus>

[0043] Figure 11 is a diagram for explaining an image forming apparatus 1 to which the present embodiment is applied. The image forming apparatus 1 according to the present embodiment includes a paper supply unit 1A, a printing unit 1B, and a paper discharge unit 1C. The paper supply unit 1A includes a first paper storage section 11 to a fourth paper storage section 14 for storing paper P as an example of a recording medium. In addition, the paper supply unit 1A is provided with delivery rollers 15 to 18, which are respectively provided corresponding to the first paper storage section 11 to the fourth paper storage section 14, and deliver the paper P stored in each paper storage section to a conveying path connected to the printing unit 1B.

[0044] The printing unit 1B includes an image forming unit 20 for forming an image on a sheet of paper P. In addition, the printing unit 1B includes a control unit 21 for controlling each unit of the image forming apparatus 1. In addition, the printing unit 1B includes an image processing unit 22. The image processing unit 22 performs image processing on image data sent from the image reading device 4 or the personal computer (PC) 5. In addition, the printing unit 1B includes a UI (User Interface) 23, which is composed of a touch panel or the like, and which notifies information to the user and receives input of information from the user.

[0045] The image forming unit 20, which is an example of an image forming unit, is provided with six image forming units 30T, 30P, 30Y, 30M, 30C, and 30K (hereinafter, sometimes simply referred to as "image forming units 30") arranged in parallel at regular intervals. Each image forming unit 30 includes: a photosensitive drum 31 that forms an electrostatic latent image while rotating in the direction of arrow A; a charging roller 32 that charges the surface of the photosensitive drum 31; a developer 33 that develops the electrostatic latent image formed on the photosensitive drum 31; and a drum cleaner 34 that removes toner and the like on the surface of the photosensitive drum 31.

[0046] In addition, the image forming unit 20 is provided with an exposure device 26 for exposing the photosensitive drum 31 of each image forming unit 30 with a laser. In addition, the exposure of the photosensitive drum 31 by the exposure device 26 is not limited to the use of a laser beam. For example, a light source such as an LED (Light Emitting Diode) may be provided in each image forming unit 30, and the photosensitive drum 31 may be exposed using light emitted from the light source.

[0047] Each image forming unit 30 is similarly configured except for the toner stored in the developer 33. The image forming units 30Y, 30M, 30C, and 30K form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. In addition, the image forming units 30T and 30P form toner images using toners corresponding to corporate colors, foaming toners for Braille, fluorescent toners, toners for improving gloss, and the like. In other words, the image forming units 30T and 30P form toner images using toners of special colors.

[0048] In addition, the image forming section 20 is provided with an intermediate transfer belt 41 to which the toner images of the respective colors formed on the photosensitive drums 31 of the respective image forming units 30 are transferred. In addition, the image forming section 20 is provided with a primary transfer roller 42 to transfer the toner images of the respective colors of the respective image forming units 30 to the intermediate transfer belt 41 through the primary transfer section T1. In addition, the image forming section 20 is provided with a secondary transfer roller 40 to transfer the toner images transferred to the intermediate transfer belt 41 to the paper P at the same time through the secondary transfer section T2. ​​Furthermore, the image forming section 20 is provided with a belt cleaner 45 to remove the toner and the like on the surface of the intermediate transfer belt 41 and a fixing device 80 to fix the secondary transferred image on the paper P.

[0049] The image forming section 20 performs an image forming operation based on a control signal from the control section 21. Specifically, in the image forming section 20, first, image processing is performed by the image processing section 22 on image data input from the image reading device 4 or the PC 5, and the image data after image processing is supplied to the exposure device 26. Then, for example, in the image forming unit 30M for magenta (M), the surface of the photosensitive drum 31 is charged by the charging roller 32, and then the exposure device 26 irradiates the photosensitive drum 31 with laser light modulated by the image data obtained from the image processing section 22.

[0050] As a result, an electrostatic latent image is formed on the photosensitive drum 31. The formed electrostatic latent image is developed by the developer 33, and a magenta toner image is formed on the photosensitive drum 31. Similarly, yellow, cyan, and black toner images are formed in the image forming units 30Y, 30C, and 30K, and special color toner images are formed in the image forming units 30T and 30P.

[0051] The color toner images formed in the image forming units 30 are electrostatically transferred to the surfaces along the image forming units 30 in sequence by the primary transfer rollers 42. Figure 1The intermediate transfer belt 41 rotates in the direction of arrow C, and overlapping toner images are formed on the intermediate transfer belt 41. The overlapping toner images formed on the intermediate transfer belt 41 are conveyed to the secondary transfer portion T2 composed of the secondary transfer roller 40 and the backup roller 49 as the intermediate transfer belt 41 moves.

[0052] On the other hand, the paper P is taken out from the first paper storage section 11 by, for example, the delivery roller 15, and then is conveyed to the position of the resist roller 74 via the conveying path. When the superimposed toner image is conveyed to the secondary transfer section T2, the paper P is supplied from the resist roller 74 to the secondary transfer section T2 according to the timing. In addition, in the secondary transfer section T2, the superimposed toner image is electrostatically transferred onto the paper P by the transfer electric field formed between the secondary transfer roller 40 and the backup roller 49.

[0053] Then, the paper P to which the superimposed toner image is electrostatically transferred is conveyed to the fixing device 80. In the fixing device 80, the paper P to which the unfixed toner image is formed is pressed and heated, and the toner image is fixed to the paper P. Then, the paper P after the fixing process passes through the curl correction section 81 provided in the paper discharge unit 1C, and is conveyed to a paper loading section (not shown).

[0054] <Structure of the Development Device 33>

[0055] Figure 2 It is a diagram showing the internal structure of the developing device 33. Figure 2 So from Figure 1 The front side (at the Figure 1 In the paper, the front side) toward the back side (in Figure 1 , which is a three-dimensional view of the developer 33 observed from the direction of the inner side of the paper, and is a cross-sectional view with the front side cut off.

[0056] The developer 33 is adjacent to the photosensitive drum 31 and has a storage section 331 composed of a frame body and is arranged in a manner extending from the front side to the back side of the printing unit 1B. In the storage section 331, an opening section 331a is provided at a position opposite to the photosensitive drum 31. Inside the storage section 331, a developing roller 332, a pickup roller 333, a first conveying section 334, a second conveying section 335, a third conveying section 336, a limiting member 337, and a removing member 338 are stored together with the developer. Each component inside the storage section 331 is a long strip component of the same length and is arranged roughly in parallel. The developer stored in the storage section 331 is composed of a mixture of a colorant for forming an image and magnetic particles, i.e., a carrier, for conveying the colorant. The developer 33 is an example of a developer unit.

[0057] The developing roller 332 includes a cylindrical shaft member and a cylindrical sleeve covering the shaft member. The developing roller 332 is arranged so that a part of the side surface is exposed from the opening 331a of the storage portion 331, and the exposed surface is opposite to the photosensitive drum 31. The shaft member of the developing roller 332 has a magnetic force, and the sleeve rotates around the shaft member in the direction of the arrow shown in the figure. The developing roller 332 adsorbs the developer to the surface of the sleeve by the magnetic force of the shaft member, and transports the developer to the opening 331a by rotating the sleeve, and develops the electrostatic latent image by attaching the colorant to the charged photosensitive drum 31. The developing roller 332 is an example of a developer retainer.

[0058] The pickup roller 333 is arranged parallel to and adjacent to the developing roller 332. The pickup roller 333 includes a cylindrical shaft member and a cylindrical sleeve covering the shaft member. The shaft member has a magnetic force, and the sleeve rotates around the shaft member. The pickup roller 333 causes the developer to be adsorbed on the surface of the sleeve by the magnetic force of the shaft member, and the developer is transported and delivered to the developing roller 332 by rotating the sleeve.

[0059] The first conveying part 334, the second conveying part 335, and the third conveying part 336 are screw conveyors having spiral blades around the rotation axis. The first conveying part 334, the second conveying part 335, and the third conveying part 336 are arranged inside the storage part 331 so that the rotation axis is parallel to the developing roller 332 and the pickup roller 333. The developer is stirred by rotating the first conveying part 334, the second conveying part 335, and the third conveying part 336 around the rotation axis, and is conveyed in the direction along the rotation axis of each conveying part 334 to 336. In addition, the developer is conveyed to the first conveying part 334, the second conveying part 335, and the third conveying part 336 in sequence as the first conveying part 334, the second conveying part 335, and the third conveying part 336 rotate, and is supplied to the pickup roller 333 from the third conveying part 336.

[0060] The limiting member 337 is provided along the side surface of the developing roller 332, on the downstream side of the position where the developing roller 332 faces the pickup roller 333, and on the upstream side of the position where the developing roller 332 faces the photosensitive drum 31. Here, the downstream side and the upstream side are the downstream side and the upstream side in the rotation direction of the developing roller 332. The limiting member 337 scrapes off the developer supplied from the pickup roller 333 and held on the surface of the developing roller 332 to limit it to a constant height. The developer scraped off by the limiting member 337 is recovered inside the storage section 331 and returned to the conveying path formed by the first conveying section 334, the second conveying section 335, and the third conveying section 336.

[0061] The removal member 338 is provided along the side of the developing roller 332 at the downstream side of the position where the developing roller 332 and the photosensitive drum 31 are opposed. The downstream side is the downstream side in the rotation direction of the developing roller 332. The removal member 338 scrapes off the developer remaining on the surface of the developing roller 332 after the developing roller 332 supplies the developer to the photosensitive drum 31. The developer scraped off from the developing roller 332 by the removal member 338 is recovered inside the storage section 331 and returned to the conveying path formed by the first conveying section 334, the second conveying section 335, and the third conveying section 336.

[0062] <Structure of Image Forming Unit 30 >

[0063] Figure 3 is a diagram showing a configuration example of the image forming unit 30. Figure 3 , a photosensitive drum 31, a developer 33, and a drum cleaner 34 are shown, but a charging roller 32 is not shown. The photosensitive drum 31, the developer 33, the drum cleaner 34, and the charging roller 32 (not shown) are arranged to extend from the front side to the back side of the printing unit 1B.

[0064] like Figure 3 As shown in FIG. 1 , the photosensitive drum 31 and the developer 33 are arranged adjacent to each other. More specifically, the photosensitive drum 31 and the developer 33 are arranged as the photosensitive drum 31 and the developer roller 332 of the developer 33 (see FIG. 1 ). Figure 2 ) is parallel to the axial direction, and a preset gap is maintained between the surface of the photosensitive drum 31 and the surface of the developing roller 332. The gap between the photosensitive drum 31 and the developing roller 332 is, for example, 0.2 mm with a tolerance of about 30 μm. The drum cleaner 34 is arranged on the opposite side of the developing device 33 across the photosensitive drum 31.

[0065] The photosensitive drum 31 is rotatably supported at both ends on the front and back sides by the drum holding portion 311. The drum holding portions 311 on the front and back sides are provided with contact support portions 312 for positioning the developer 33. Figure 3 In the figure, there is a contact support portion 312 provided on the drum holding portion 311 on the front side. The photosensitive drum 31 and the drum holding portion 311 are an example of an image holding body unit. In addition, here, the contact support portion 312 is provided on each drum holding portion 311 on the front side and the back side, but it can also be set as a structure that is provided only on either one.

[0066] The developing device 33 is supported by the frame 330. On each of the front and rear parts of the frame 330, a contact part 33a corresponding to the contact support part 312 of the drum holding part 311 is provided. Figure 3, a contact portion 33a is shown disposed on the front side. As will be described in detail later, the developer 33 is supported by the frame 330 and the support member 50 located at the bottom of the developer 33 so as to tilt toward the photosensitive drum 31. Moreover, by tilting the developer 33 toward the photosensitive drum 31, the contact portion 33a abuts against the contact support portion 312 of the drum holding portion 311, thereby positioning the developer 33 relative to the photosensitive drum 31. The developer 33 including the frame 330 is an example of a developer unit. The contact support portion 312 of the drum holding portion 311 and the contact portion 33a of the developer 33 are examples of a second positioning portion. In addition, the contact portion 33a is disposed on the front side and the back side of the frame 330, respectively, but it may also be configured such that, in the case where the contact support portion 312 is disposed only on either the front side or the back side, the contact support portion 312 is disposed only on either the front side or the back side, corresponding to the contact support portion 312.

[0067] <Supporting structure of the developer 33>

[0068] Figure 4 33 is a diagram showing the overall structure of the developing device 33. Support rollers 330a and 330b for supporting the developing device 33 are provided at the lower and upper parts of the frame 330 supporting the developing device 33. The lower support roller 330a and the upper support roller 330b are placed on the supporting member 50 (see FIG. Figure 3 ) is supported on the support member 50. As will be described in detail later, the support member 50 includes rails for supporting the lower support roller 330a and the upper support roller 330b, respectively. The rails of the support member 50 are provided, for example, two by two, on the front side and the back side of the printing unit 1B with respect to each of the lower support roller 330a and the upper support roller 330b. By placing the lower support roller 330a and the upper support roller 330b on the rails of the support member 50, the developer 33 can move along the rails of the support member 50. The support member 50 is an example of a supporting portion.

[0069] In the example shown in the figure, when viewed from the front side of the printing unit 1B, a lower support roller 330a is provided at the lower right, and an upper support roller 330b is provided at the upper left. Figure 3 ) is one side, and is provided at a position on the other side of the center of gravity of the developer 33. The upper support roller 330b is provided at a position on the front side of the center of gravity of the developer 33. The position of the upper support roller 330b is not limited to any position as long as it can stably support the developer 33 together with the lower support roller 330a. Figure 4 Thus, by providing the lower support roller 330a and the upper support roller 330b, when the upper support roller 330b is away from the track and the developer 33 is supported only by the lower support roller 330a at the rear side relative to the center of gravity, the developer 33 tilts forward.

[0070] Figure 5 is a diagram schematically showing a supporting structure of the developer 33, Figure 5 (A) is a diagram showing the support structure of the front side of the lower support roller 330a. Figure 5 (B) is a diagram showing the support structure of the back side of the lower support roller 330a. Figure 5 (C) is a diagram showing the support structure of the front side of the upper support roller 330b. Figure 5 (D) is a diagram showing the support structure of the back side of the upper support roller 330b. Figure 5 As shown in (A) to (D) of FIG. 5 , as the support member 50, corresponding tracks are respectively provided on the front side and the back side of the lower support roller 330a, and corresponding tracks are respectively provided on the front side and the back side of the upper support roller 330b. Figure 5 The track corresponding to the front side of the lower support roller 330a shown in (A) is set as the lower first support part 51, which is connected with Figure 5 The track corresponding to the back side of the lower support roller 330a shown in (B) is set as the lower second support part 52, which is connected with Figure 5 The track corresponding to the front side of the upper support roller 330b shown in (C) is set as the upper first support part 53, which is connected with Figure 5 The rail corresponding to the back side of the upper support roller 330 b shown in (D) is set as the upper second support part 54.

[0071] like Figure 5 As shown in (A), the lower first support portion 51 has an inclined portion 51a that is inclined downward toward the front end at one end side, and a substantially horizontal retreat portion 51b at the other end side. A stop portion 51c extending upward is formed at the front end of the inclined portion 51a. The lower support roller 330a mounted on the lower first support portion 51 is located at the inclined portion 51a (at the bottom) during normal operation of image formation. Figure 5 When the developer 33 is pulled out from the printing unit 1B for replacement of parts or developer, etc., it retreats to the retreat portion 51b (in Figure 5 In (A), it is recorded with a dotted line).

[0072] When the lower support roller 330a is located at the inclined portion 51a, the lower support roller 330a is in a state where a force is applied downward (toward the front end) along the inclination of the inclined portion 51a due to the load of the developer 33. Moreover, the lower support roller 330a is positioned by abutting against the abutting portion 51c at the front end of the inclined portion 51a. In addition, in order to prevent the lower support roller 330a from retreating in the direction of the inclination of the inclined portion 51a due to vibration during image formation, a pressing member 55 is installed on the lower first support portion 51 in a state where the lower support roller 330a abuts against the abutting portion 51c, and the movement of the lower support roller 330a is restricted by the pressing member 55.

[0073] like Figure 5 As shown in (B), the lower second support portion 52 has an inclined portion 52a that is inclined downward toward the front end at one end side, and a substantially horizontal retreat portion 52b at the other end side. The positions and lengths of the inclined portion 52a and the retreat portion 52b are similar to those of the reference Figure 5 The lower support roller 330a placed on the lower second support portion 52 is located at the inclined portion 52a (at the bottom) during normal operation of image formation. Figure 5 When the developer 33 is pulled out from the printing unit 1B for replacement of parts or developer, etc., it retreats to the retreat portion 52b (in Figure 5 (B), recorded with a dotted line).

[0074] The lower second support portion 52 is not provided with a structure that restricts the movement of the lower support roller 330a, such as the abutment portion 51c and the pressing member 55 in the lower first support portion 51. Therefore, the lower support roller 330a can also move on the inclined portion 52a of the lower second support portion 52 during normal operation. That is, the positioning of the lower support roller 330a by the lower second support portion 52 is performed only by placing the lower support roller 330a on the lower second support portion 52, which is looser than the positioning of the lower first support portion 51. This is to avoid excessive physical load being applied to the developer 33. The positioning of the developer 33 during normal operation is performed at four locations, namely, the contact support portion 312 of the drum holding portion 311 and the contact portion 33a of the frame 330 of the developer 33, the lower first support portion 51, and the lower second support portion 52. Here, if the positions of all four locations are fixed, there is a possibility that excessive physical load is applied to the developer 33 due to vibration and load. Therefore, the load acting on the developing device 33 is reduced by loosely positioning the lower support roller 330a in the lower second support portion 52. The lower first support portion 51 and the lower second support portion 52 are examples of the lower guide path and are examples of the first positioning portion.

[0075] like Figure 5 As shown in (C), the upper first support portion 53 has an inclined portion 53a on one end side that is inclined downward toward the front end, and a substantially horizontal retreat portion 53b on the other end side. A support piece 53c protruding upward is formed at the front end of the inclined portion 53a. The upper support roller 330b mounted on the upper first support portion 53 moves to the position of the inclined portion 53a (at the position of the inclined portion 53a) when the developer 33 is set to the position for normal operation of image formation. Figure 5In addition, when the developer 33 is pulled out from the printing unit 1B due to replacement of parts or developer, the upper support roller 330b retreats to the retreat portion 53b (in Figure 5 (C), recorded with a dotted line).

[0076] In addition, if Figure 5 As shown by the dotted line in (C), the upper first support portion 53 is configured to enable the inclined portion 53a and the support piece 53c to be retracted downward. Specifically, for example, a rotating shaft (not shown) is provided at the lower portion of the retracting portion 53b, and the upper first support portion 53 is retracted by rotating it around the rotating shaft in the direction of the arrow D. When the upper first support portion 53 is retracted downward, the upper support roller 330b is removed from the upper first support portion 53. As described in detail later, when performing normal operation of image formation, the upper first support portion 53 is retracted after the upper support roller 330b is located at the inclined portion 53a. Hereinafter, the state of the upper first support portion 53 when the upper support roller 330b is in contact with the inclined portion 53a of the upper first support portion 53 is referred to as the first state, and the state of the upper first support portion 53 when the upper first support portion 53 is retracted and separated from the upper support roller 330b is referred to as the second state.

[0077] like Figure 5 As shown in (D), the upper second support portion 54 is composed of a substantially horizontal portion. The position and length of the upper second support portion 54 are similar to those of the reference Figure 5 Therefore, when the developer 33 is pulled out from the printing unit 1B for replacement of parts or developer, the upper support roller 330b is placed on the upper second support part 54 (at Figure 5 In (D), the upper support roller 330b is separated from the upper second support portion 54 (in FIG. 1 ). Figure 5 In (D), it is indicated by a solid line.) In addition, the upper first support portion 53 and the upper second support portion 54 are examples of an upper guide path.

[0078] <Operation during installation of the developing device 33>

[0079] Figure 6 to Figure 9 It is a diagram showing the operation when the developing device 33 is installed. Figure 6 33 is a diagram showing a state where the developing unit 33 is retracted. Figure 6 (A) is a diagram showing the state of the front side, Figure 6 (B) is a diagram showing the state of the back side. Figure 7 3 is a diagram showing a state where the developing unit 33 moves from the retreat position to the setting position. Figure 7(A) is a diagram showing the state of the front side, Figure 7 (B) is a diagram showing the state of the back side. Figure 8 33 is a diagram showing a state where the development device 33 has completed moving to the setting position. Figure 8 (A) is a diagram showing the state of the front side, Figure 8 (B) is a diagram showing the state of the back side. Fig. 9 2 is a diagram showing a state in which the developing device 33 is set. Fig. 9 (A) is a diagram showing the state of the front side, Fig. 9 (B) is a diagram showing the state of the back side. Figure 6 (B) Figure 7 (B) Figure 8 (B) Fig. 9 (B) shows the back side viewed from the front side, so the outer shapes of the photosensitive drum 31 and the developer 33 are shown by virtual lines (dashed lines).

[0080] The developing device 33 is in the retracted state when the developing device 33 is withdrawn from the printing unit 1B for replacement of parts or developer, etc. When the developing device 33 is in the retracted state, Figure 6 As shown in (A) and (B), the lower support roller 330a is located at the retreat portion 51b of the lower first support portion 51 (refer to Figure 5 ) and the retreat portion 52b of the lower second support portion 52 (refer to Figure 5 ). In addition, the upper support roller 330b is located in the retreat portion 53b of the upper first support portion 53 in the first state (refer to Figure 5 ) and the upper second support portion 54.

[0081] When the developing device 33 is transferred from the retracted state to the set state for using the image forming apparatus 1, the developing device 33 moves from the retracted position to the photosensitive drum 31 side. Figure 7 As shown in (A) and (B), the lower support roller 330a is moved from the retreat portion 51b of the lower first support portion 51 toward the inclined portion 51a (refer to Figure 5 ) and moves from the retreat portion 52b of the lower second support portion 52 toward the inclined portion 52a (refer to Figure 5 ) is moved. In addition, the upper support roller 330b moves from the retreat portion 53b of the upper first support portion 53 in the first state toward the inclined portion 53a (refer to Figure 5 ) moves, and moves the upper second support portion 54 toward the end portion on the photosensitive drum 31 side.

[0082] When the movement of the developing device 33 is completed, the developing device 33 is in the setting preparation state. Figure 8As shown in (A) and (B) of FIG. 1 , the lower support roller 330a is located at the inclined portion 51a of the lower first support portion 51 and the inclined portion 52a of the lower second support portion 52. In addition, the upper support roller 330b is located at the inclined portion 53a of the upper first support portion 53 in the first state and is separated from the upper second support portion 54. In the setting preparation state, the developer 33 is supported by the lower first support portion 51 and the lower second support portion 52, and is supported by the inclined portion 53a of the upper first support portion 53 and the support sheet 53c (see FIG. 1 ). Figure 5 ) to support the tilting toward the photosensitive drum 31. Figure 8 As shown in (B), in the setting preparation state, the upper second support portion 54 is separated from the upper support roller 330 b and therefore does not support the developer 33 .

[0083] In the setting preparation state, when the upper first support portion 53 transitions from the first state to the second state, as shown in FIG. Fig. 9 As shown in (A) and (B), the support from the inclined portion 53a and the support piece 53c of the upper first support portion 53 is lost, so the developer 33 tilts toward the photosensitive drum 31. In addition, the frame 330 (see Figure 3 ) contacts the contact support portion 312 of the drum holding portion 311 of the photosensitive drum 31, supporting the developer 33 tilted toward the photosensitive drum 31. Fig. 9 As shown in (A), a pressing member 55 is installed on the front lower first support portion 51, and the lower support roller 330a is fixed by the inclined portion 51a, the abutting portion 51c and the pressing member 55 of the lower first support portion 51. Thus, the developer 33 is positioned and the posture of the developer 33 is stabilized.

[0084] <Drive mechanism>

[0085] Next, the driving mechanism of the developing device 33 is described. The developing device 33 includes a motor as a driving source, and transmits the driving force of the motor to the developing roller 332, the pickup roller 333, the first conveying portion 334, the second conveying portion 335, and the third conveying portion 336 (see Figure 2 ), the developer contained in the developing device 33 is supplied to the developing roller 332. Then, the toner of the developer held on the developing roller 332 causes the photosensitive drum 31 to develop.

[0086] Fig.10: is a diagram showing the driving mechanism of the developer 33. The driving mechanism 60 is provided at an end portion of one end side (for example, the front side) of the developer 33, and has a motor 61 as a driving source. The motor 61 is connected to the driving shaft 63 via gears, and the rotation of the motor 61 around the axis of the driving shaft 63 is transmitted to the transmission shaft 339 of the developer 33. Furthermore, the rotation around the axis of the transmission shaft 339 is dispersed via gears, etc., to drive the developing roller 332, the pickup roller 333, and the first to third conveying parts 334 to 336. In addition, in Fig.10 In the embodiment, the gear connecting the motor 61 and the drive shaft 63 is housed in the housing 64 .

[0087] Here, the developer 33 may be offset in the axial position of the transmission shaft 339 due to individual differences or changes over time. Figure 5 , 6 As described above, a part of the lower support roller 330a of the developer 33 is fixed by the lower first support portion 51, and on the other hand, there is a certain degree of freedom in positioning based on the lower second support portion 52. This support structure may cause the axial center position of the transmission shaft 339 to shift. Therefore, in the drive mechanism 60 including the motor 61, it is set to be able to change the position of the axial center of the shaft joint (coupling) 66 connecting the drive shaft 63 and the transmission shaft 339 of the developer 33.

[0088] Figure 11 to Figure 14 It is a diagram showing the procedure of adjusting the axis center in the driving mechanism 60 of the developing device 33 . Fig.11 (A) is a diagram showing the first state, Fig.11 (B) is a diagram showing the second state. Fig.12 (A) is a diagram showing the third state, Fig.12 (B) is a diagram showing the fourth state. Fig.13 (A) is a diagram showing the fifth state, Fig.13 (B) is a diagram showing the sixth state. Fig.14 (A) is a diagram showing the seventh state, Fig.14 (B) is a diagram showing the eighth state.

[0089] like Fig.11As shown in (A), the driving mechanism 60 includes a motor 61, a gear 62 for transmitting the driving force of the motor 61, and a driving shaft 63. The gear 62 and the driving shaft 63 are housed in a housing 64, and one end of the driving shaft 63 protrudes from the housing 64. The rotation of the shaft of the motor 61 is transmitted to the driving shaft 63 via the gear 62. Moreover, the portion of the driving shaft 63 exposed from the housing 64 rotates to supply driving force to the outside. The housing 64 is mounted on the frame 330 of the developer 33 by means of screws 64a. The screw holes (not shown) of the housing 64 for inserting the screws 64a can adjust the position of the housing 64 relative to the frame 330, for example, by tightening the screws 64a at different positions of the long holes, i.e., the screw holes.

[0090] When adjusting the axis center of the driving mechanism 60 (i.e., the position of the axis of the driving shaft 63), as shown in FIG. Fig.11 As shown in (B), first, the adjustment fixture 65 is installed on the portion of the drive shaft 63 exposed from the housing 64. The adjustment fixture 65 is a cylindrical fixture made of metal or the like. Fig.12 As shown in (A) and (B), the position of the drive shaft 63 of the drive mechanism 60 equipped with the adjustment fixture 65 is aligned with the transmission shaft 339 of the developer 33. Fig.12 In the state shown in (A), the positions of the drive shaft 63 and the transmission shaft 339 are not consistent. Therefore, remove the screw 64a, as shown in FIG. Fig.12 As shown in (B), the housing 64 is moved to align the positions of the drive shaft 63 and the transmission shaft 339. Then, the adjustment jig 65 of the drive shaft 63 is slid so that the adjustment jig 65 spans the drive shaft 63 and the transmission shaft 339.

[0091] Then, if Fig.13 As shown in (A), the housing 64 is fixed to the frame 330 of the developer 33 by screws 64a while the driving shaft 63 and the transmission shaft 339 are aligned by adjusting the jig 65. After the housing 64 is fixed, Fig.13 As shown in (B), the transmission shaft 339 of the developer 33 is removed from the adjustment fixture 65, and then, as shown in Fig.14 As shown in (A), the adjustment jig 65 is removed from the drive shaft 63, and the shaft joint 66 is installed on the drive shaft 63 instead. Then, the other end side of the shaft joint 66 installed on the drive shaft 63 is installed on the transmission shaft 339 of the developer 33. Through the above steps, the axis centers of the drive shaft 63 of the drive mechanism 60 and the transmission shaft 339 of the developer 33 are adjusted, and they are connected via the shaft joint 66.

[0092] Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above embodiments. Various changes or structural substitutions that do not depart from the scope of the technical concept of the present invention are included in the present invention.

[0093] <Note>

[0094] (((1)))A developing device, characterized by comprising:

[0095] An image retaining body unit, the image retaining body unit having an image retaining body; a developer unit, the developer unit having a developer retaining body for supplying developer to the image retaining body on which an electrostatic latent image is formed; a supporting portion, the supporting portion supporting the developer unit so as to be able to move forward and backward relative to the image retaining body unit; a first positioning portion, the first positioning portion being provided at an end portion of the supporting portion on the image retaining body unit side for positioning the developer unit; and a second positioning portion, the second positioning portion maintaining a predetermined gap between the developer retaining body and the image retaining body to position the developer unit when the developer unit is positioned by the first positioning portion and tilted toward the image retaining body unit side.

[0096] (((2)))The developing device according to (((1))), wherein:

[0097] The support portion has a guide path for guiding the developer unit, and the first positioning portion is configured to tilt an end of the guide path so that the image holding body unit side is lowered, and has a contact portion for the developer unit to contact at a position where the guide path is tilted.

[0098] (((3)))The developing device according to (((1))) or (((2))), wherein:

[0099] The first positioning portion further includes a pressing member configured to restrict movement of the developing device unit in a state in which the developing device unit abuts against the abutting portion.

[0100] (((4)))The developing device according to (((2))) or (((3))), wherein:

[0101] The guide path of the support portion includes two rails arranged in parallel along the direction in which the developer unit advances and retreats, and the first positioning portion is configured such that the ends of the two rails are inclined and the end of one of the two rails includes the abutment portion.

[0102] (((5)))The developing device according to (((4))), wherein:

[0103] The developer unit is not fixed to the rail without the abutment portion among the two rails of the first positioning portion.

[0104] (((6)))The developing device according to any one of (((1))) to (((5))), wherein

[0105] The supporting portion comprises: a lower guide path, which supports and guides the lower portion of the developer unit and has the first positioning portion; and an upper guide path, which supports and guides the upper portion of the developer unit, and when the developer unit is positioned by the first positioning portion of the lower guide path, the developer unit is separated from the upper guide path and tilted toward the image holding body unit side.

[0106] (((7)))The developing device according to (((6))), wherein:

[0107] When at least the developer unit is positioned by the first positioning portion of the lower guide path, the upper guide path of the support portion can switch between a contact state of supporting the developer unit and a retracted state of being separated from the developer unit.

[0108] (((8)))The developing device according to (((7))), wherein:

[0109] The upper guide path of the support portion has two rails arranged in parallel along the direction of advance and retreat of the developer unit, one of the two rails in the upper guide path can switch between the contact state and the retreat state, and the other of the two rails in the upper guide path is shorter than the moving distance of the developer unit and does not contact the developer unit when the developer unit is in the position positioned by the first positioning portion of the lower guide path.

[0110] (((9)))The developing device according to any one of (((1))) to (((8))), wherein

[0111] A driving mechanism is further provided for rotating a driving shaft of the developer unit and transmitting a driving force to the developer unit, wherein the driving mechanism is capable of changing a position of an axial center of a joint portion connected to the driving shaft and rotating the driving shaft.

[0112] (((10)))An image forming device, wherein:

[0113] A developing device is provided according to any one of (((1))) to (((9))).

[0114] According to the developing device involved in (((1))), the developing device can be pressed against the photosensitive drum by a simple structure using the load of the developing device unit, compared with a structure using a member that generates a pressing force to press the developing device against the photosensitive drum.

[0115] According to the developing device according to (((2))), compared with a structure in which a mechanism for fixing the developing unit is provided, the developing unit is positioned by its own weight, so that a simple structure can be adopted.

[0116] According to the developing device of (((3))), the restriction of the movement of the developing unit can be suppressed more reliably compared with a structure in which the movement of the developing unit is restricted only by the inclination of the guide path and the abutment portion.

[0117] According to the developing device according to (((4))), a simpler structure can be adopted compared with a structure in which each rail has a contact portion.

[0118] According to the developing device involved in (((5))), compared with a structure in which the developing unit is fixed to each rail, the developing unit can be positioned more easily and the load on the developing unit and the first positioning portion can be reduced.

[0119] According to the developing device involved in (((6))), compared with a structure in which a mechanism for fixing the developing unit is provided, the developing unit is positioned by its own weight, so that a simple structure can be adopted.

[0120] According to the developing device of (((7))), compared with a configuration in which the upper guide path does not support the developing unit on the first positioning portion, the falling motion of the developing unit can be suppressed.

[0121] According to the developing device involved in (((8))), a simple structure can be adopted as compared with a structure capable of switching between the contact state and the retracted state on each rail.

[0122] According to the developing device involved in (((9))), compared with a structure in which the axial center position of the driving mechanism is fixed, it is possible to cope with the deviation of the axial center caused by individual differences or time changes in the developing device units.

[0123] According to the image forming apparatus of (((10))), compared with a structure in which a component that generates a pressing force to press the developer toward the photosensitive drum is used in the developing device, the developer can be pressed toward the photosensitive drum by a simple structure utilizing the load of the developer unit.

Claims

1. A developing device, characterized in that: have: An image holding body unit, the image holding body unit having an image holding body; a developer unit having a developer holding body for supplying developer to the image holding body on which the electrostatic latent image is formed; a supporting portion that supports the developer unit so as to be able to move forward and backward relative to the image holding body unit; a first positioning portion provided at an end portion of the support portion on the image holding body unit side to position the developer unit; as well as The second positioning portion positions the developer unit by maintaining a predetermined gap between the developer holding member and the image holding member when the developer unit is positioned by the first positioning portion and tilted toward the image holding member.

2. The developing device according to claim 1, wherein: The supporting portion has a guide path for guiding the developer unit, The first positioning portion is configured such that an end portion of the guide path is inclined so that the image holding body unit side is lowered, and has a contact portion against which the developer unit contacts at a position where the guide path is inclined.

3. The developing device according to claim 1 or 2, wherein: The first positioning portion further includes a pressing member configured to restrict movement of the developing device unit in a state in which the developing device unit abuts against the abutting portion.

4. The developing device according to claim 2 or 3, wherein: The guide path of the support portion has two rails arranged in parallel along the direction in which the developer unit advances and retreats. The first positioning portion is configured such that the ends of the two rails are inclined, and the end of one of the two rails has the abutment portion.

5. The developing device according to claim 4, wherein: The developer unit is not fixed to the rail without the abutment portion among the two rails of the first positioning portion.

6. The developing device according to any one of claims 1 to 5, wherein: The support portion comprises: a lower guide path that supports and guides a lower portion of the developer unit and has the first positioning portion; and an upper guide path that supports and guides an upper portion of the developer unit, In a state where the developer unit is positioned by the first positioning portion of the lower guide path, the developer unit separates from the upper guide path and falls toward the image holding body unit side.

7. The developing device according to claim 6, wherein: When at least the developer unit is positioned by the first positioning portion of the lower guide path, the upper guide path of the support portion can switch between a contact state of supporting the developer unit and a retracted state of separating from the developer unit.

8. The developing device according to claim 7, wherein: The upper guide path of the support portion has two rails arranged in parallel along the direction in which the developer unit advances and retreats. One of the two rails in the upper guide path is capable of switching between the contact state and the retracted state, The other of the two rails in the upper guide path is shorter than a moving distance of the developer unit and does not contact the developer unit when the developer unit is positioned by the first positioning portion of the lower guide path.

9. The developing device according to any one of claims 1 to 8, wherein: A driving mechanism is further provided, the driving mechanism rotating the driving shaft of the developing unit and transmitting driving force to the developing unit, The driving mechanism is capable of changing the position of the axis center of a joint portion that is connected to the driving shaft and rotates the driving shaft.

10. An image forming device, characterized in that: A developing device according to any one of claims 1 to 9 is provided.

Images